Method and system for controlling a turbocharged engine during an upshift

Abstract

A method for propulsion of a vehicle ( 100 ) having a combustion engine ( 101 ) and a gearbox. ( 103 ), the engine ( 101 ) having a combustion chamber with an inlet for supply of combustion gas and an outlet for evacuation of exhaust gas, the method includes, during a change of gear from a first higher to a second lower gear ratio, increasing the pressure (P ut ) at the chamber outlet ( 202 ) with a turbocharger unit and, when the rate of revolution (n) of the combustion engine ( 101 ) has at least partially fallen, controlling the turbocharger unit ( 203 ) such that the combustion gas pressure (P in ) is increased.

The invention claimed is: 
     
       1. A method for the propulsion of a vehicle, wherein the vehicle comprises:
 a combustion engine having a rotatable shaft, a gearbox connected to the engine shaft and the gearbox is adjustable to a number of gear ratios for transfer of a force between the combustion engine and at least one driving wheel of the vehicle; 
 the combustion engine comprises at least one combustion chamber with at least one inlet for supply of combustion gas and at least one outlet for evacuation of an exhaust gas flow that results from combustion of the combustion gas in the combustion chamber; 
 the method comprises: 
 during a change of gear in the gearbox from a first higher gear ratio to a second lower gear ratio, wherein a rate of revolution of the combustion engine shaft is reduced from a first rate of revolution (n 1 ) to a second rate of revolution (n 2 ): 
 increasing the pressure (P ut ) at the outlet from the combustion chamber at least through the use of a turbocharger unit which is configured for constriction of the exhaust gas flow; 
 reducing the pressure (P in ) at the combustion gas inlet through the opening of a first valve; and 
 when the first rate of revolution (n 1 ) of the combustion engine shaft has at least partially fallen towards the said second rate of revolution (n 2 ), controlling the turbocharger unit such that the combustion gas pressure (P in ) is increased. 
 
     
     
       2. The method according to  claim 1 , further comprising:
 at least partially increasing the pressure (P ut ) at the outlet before the first valve is opened. 
 
     
     
       3. The method according to  claim 1 , further comprising at least partially increasing the pressure (P ut ) at the outlet through increasing a fraction of the exhaust gas flow from combustion in the combustion chamber that is led through a turbine of the turbocharger unit for driving the turbine. 
     
     
       4. The method according to  claim 3 , wherein the exhaust gas flow that results from the combustion in the combustion chamber and is led through the turbine of the turbocharger unit for driving the turbine is regulated through use of a second valve located and configured for diversion of the complete exhaust gas flow, or a part of the exhaust gas flow, past the turbine. 
     
     
       5. The method according to  claim 1 , further comprising at least partially increasing the pressure (P ut ) at the outlet of the combustion chamber through regulating the turbine such that the fraction of the exhaust gas flow from the combustion in the combustion chamber is increased and is used to drive the turbine of the turbocharger unit. 
     
     
       6. The method according to  claim 3 , further comprising regulating the turbine such that the turbine has a rate of revolution in the range of 30-100% of the maximum working rate of revolution of the turbine. 
     
     
       7. The method according to  claim 3 , further comprising regulating the turbine such that a rate of revolution of the turbine is essentially a maximum working rate of revolution of the turbine. 
     
     
       8. The method according to  claim 1 , further comprising maintaining the pressure (P ut ) at the outlet essentially constant during the reduction in the rate of revolution, at least until starting the raising of the combustion gas pressure. 
     
     
       9. The method according to  claim 1 , further comprising increasing the pressure (P ut ) at the outlet from the combustion chamber to a pressure that amounts to at least double the pressure that surrounds the vehicle. 
     
     
       10. The method according to  claim 1 , further comprising: increasing the pressure (P ut ) at the outlet from the combustion chamber at least partially through use of a constriction device other than the first valve, and the constriction device is arranged downstream of at least one of the combustion chamber outlet and the turbine. 
     
     
       11. The method according to  claim 1 , further comprising: increasing the pressure (P ut ) at the outlet from the combustion chamber at least partially through use of a compression brake. 
     
     
       12. The method according to  claim 1 , further comprising:
 closing the first valve during the raising of the pressure (P in ) of the combustion gas. 
 
     
     
       13. The method according to  claim 1 , further comprising:
 the controlling of the turbocharger unit and the first valve for starting an increase in the combustion gas pressure (P in ) before the rate of revolution (n) of the combustion engine shaft has fallen to the second rate of revolution (n 2 ) of the combustion engine shaft. 
 
     
     
       14. The method according to  claim 1 , further comprising starting raising of the combustion gas pressure (P in ) when the rate of revolution (n) of the combustion engine shaft has fallen to a rate of revolution (n iim ) that is constituted by a second rate of revolution (n 2 ) plus a selected value in the range of 10-50% of the difference in a rate of revolution between a first rate of revolution (n 1 ) and the second rate of revolution (n 2 ). 
     
     
       15. The method according to  claim 1 , further comprising starting the raising of the combustion gas pressure (P in ) when the rate of revolution (n) of the combustion engine shaft has fallen to a second rate of revolution (n 2 ), and before the combustion engine is reconnected with the driving wheels of the vehicle through the gearbox. 
     
     
       16. The method according to  claim 1 , further comprising maintaining a difference in pressure (ΔP motor ) between the inlet and the outlet essentially constant during the reduction of the rate of revolution (n) for the combustion engine shaft. 
     
     
       17. The method according to  claim 1 , further comprising when the pressure (P in ) of the combustion gas is reduced, controlling the pressure in the combustion chamber towards essentially the pressure that surrounds the vehicle, or at least towards a pressure that is lower than a pressure that was prevalent at the beginning of the pressure-reduction process. 
     
     
       18. The method according to  claim 1 , further comprising, during the raising of the inlet pressure (P in ), raising the outlet pressure to a higher pressure compared with the pressure at the outlet before the increase of the currently prevalent inlet pressure to reduce the reduction of the differential pressure across the combustion engine during the raising of the inlet pressure (P in ). 
     
     
       19. The method according to  claim 18 , wherein the further raising of the outlet pressure (P ut ) essentially corresponds to the increase in pressure of the inlet pressure (P in ). 
     
     
       20. The method according to  claim 18 , wherein during the further raising of the outlet pressure (P ut ), increasing the outlet pressure (P ut ) to a level that exceeds a limitation on pressure with respect to non-instantaneous pressure that is prevalent at the outlet. 
     
     
       21. The method according to  claim 1 , further comprising performing the method essentially when the combustion engine is disengaged from all of the driving wheels. 
     
     
       22. The method according to  claim 1 , further comprising starting at least one of the increase in pressure (P ut ) at the outlet and the reduction of the inlet pressure before or when the combustion engine has been completely disengaged from the driving wheels. 
     
     
       23. A system for propulsion of a vehicle, wherein the vehicle comprises:
 a combustion engine having a shaft to be driven by the engine, a gearbox between the combustion engine shaft and at least one driving wheel, wherein the gearbox is adjustable to a number of gear ratios for transfer of a force between the combustion engine and the at least one driving wheel; 
 the combustion engine comprises a combustion chamber having an inlet for supply of combustion gas and an outlet for evacuation of an exhaust gas flow that has resulted from combustion in the combustion chamber; 
 a turbocharger unit configured for pressurizing of the combustion gas in the combustion chamber; 
 during a change of gear from a first higher gear ratio to a second lower gear ratio in the gearbox, wherein a rate of revolution of the combustion engine shaft is reduced from a first rate of revolution to a second rate of revolution, the system comprising: 
 means for increasing a pressure (P ut ) at the outlet comprising at least the use of the turbocharger unit for constriction of the exhaust gas flow; 
 means for reducing the pressure (P in ) at the combustion gas outlet from the combustion chamber through opening of a valve at the combustion gas outlet; and 
 when the first rate of revolution of the combustion engine shaft has at least partially fallen towards the second rate of revolution in the combustion chamber, means for controlling the turbocharger unit such that the combustion gas pressure (P in ) in the combustion chamber is increased. 
 
     
     
       24. The system according to  claim 23 , further comprising the combustion engine is constituted by any one of the group: vehicle engine, marine engine, and industrial engine. 
     
     
       25. The system according to  claim 23 , wherein the combustion engine is comprised of several of the combustion chambers. 
     
     
       26. The system according to  claim 23 , wherein the valve is located and configured to act against the high-pressure side of a compressor at the turbocharger unit, to reduce the pressure (P in ) at the combustion gas outlet from the combustion Chamber. 
     
     
       27. The system according to  claim 26 , further comprising a second valve that is configured and operable to cause recirculation of pressurized combustion gas to an inlet side of the compressor thereby reducing inlet pressure to the combustion chamber. 
     
     
       28. A vehicle that comprises a system according to  claim 23 .